CombinedTraffic Signal Control andRouteGuidance: Multiple UserClass Traffic Assignment ModelversusDiscrete Choice Model

Intelligent Transportation Systems (ITS) arethe majorsolutions torelieving traffic congestion. Traffic signal control androuteguidance, twokeysubsystems of ITS,jointly influence traffic flowintimeandspace. Over thelast threedecades, combined traffic signal control and routeguidance (CTSCRG)hasbeenresearch emphasis. Therearetwokindsofmodelfordescribing CTSCRG: Multiple UserClass Traffic Assignment ModelandDiscrete ChoiceModel.Theintent ofthepaperistocomparethe traffic equilibrium results ofthesetwo models.For describing routeguidance systemwhichiscomposedof guideddriverand non-guided driver, theconceptof multiple userclass (MUC)isintroduced. InMUC traffic assignment model, guided drivers aremodeled ascomplete information userequilibrium traffic assignment, andnon- guided drivers aremodeledasstochastic userequilibrium traffic assignment. Indiscrete choice model, guided drivers andnon-guided drivers aremodeled asstochastic dynamic useroptimumandroutechoice modelislogit model.The perception errorofnon-guided drivers islarger thanthe perception errorof guideddrivers. In thispaper, perception erroristhefunction ofcurrent travel timeand sampledfromuniformdistribution. Becausesimulation- basedmethodcanallow morecomplex interactions andwin inreality valuethantravel timeformula, we combine HybridGeneticAlgorithmwith cellular automata simulation tocalculate travel timeandoptimize signal setting plan. Iterative simulation andassignment procedure isbuilt: Roadisdiscretized byCellular Automata. Traffic flowdynamics isrepresented byCellTransmission Model; Signal setting isoptimized byHybridGenetic Algorithm; Vehicle agentcanreceive routeguidance information and select suggested route. Comparison results showthatMUC traffic assignment modelconverge, discrete choice model doesnot converge. Averagedelayof MUC traffic assignment modelislowerthanthatofdiscrete choice model.Perception errorhasimportant influence onthe resulting performance whichisexpressed astotal delay.